2-[18F]-FDG PET/CT in rasmussen encephalitis: guiding diagnosis and treatment in a young adult with sudden onset

Rasmussen encephalitis (RE) is a rare condition characterized by a chronic inflammatory disorder due to unilateral inflammation of the cerebral cortex. Typically, it involves one cerebral hemisphere and manifests through intractable epileptic seizures. Its occurrence in adults is infrequent. We present a case of a 28year-old woman who was brought to the emergency room due to the sudden onset of uncontrolled seizures. The use of 2-[18F]-FDG PET/CT (FDG-PET) helped in the differential diagnosis between autoimmune seronegative encephalitis and Rasmussen encephalitis. Even though FDG-PET is not a mandatory diagnostic criterion in the clinical evaluation of RE patients, the presented case and the available literature suggest its usefulness as a valuable diagnostic tool in patients with uncertain diagnosis, emphasizing its potential as a reliable adjunct in challenging diagnostic scenarios and for patient follow-up.